This directory contains a coroutine.hpp header file. This self-contained
header is needed by Kea. It is part of Boost library for a long time.
Unfortunately, RedHat (and CentOS) provide only a very old version
of Boost that doesn't have coroutine.hpp header included.

This caused Kea to require building new version of Boost on RHEL and
CentOS, just for the sake of getting this 9KB header. Note that although
the coroutine is included in Boost, it does not include anything from
Boost and is self contained.

This header and the whole directory will be removed eventually once
RHEL and CentOS start providing more modern Boost version.